I've got a few servers in my home rack, switching gear, pix boxes (that do nothing... grrr) and of course cable modem. I'm drawing about 10amps at 120v. This whole thing is for testing a monitoring system design that I've been working on, and I just made a rather annoying discovery after I pulled main power-

It's been almost 30 minutes and the batteries are still over 90%. 4 12v 55AH in series to an APS2448... I'm starting to wonder exactly how long this will run, as I was only expecting it to stand up for ~10 minutes.

2 Replies

That's quite an inverter setup you've got there Magnus! Those APS models are typically used for more industrial applications or mobile applications for semi trucks, RVs and the like. The big deal with this type of inverter is that it's setup to run inductive loads -- like motors, compressors, etc... where the equipment pulls lots of power on startup (something that IT-style UPS systems have a hard time doing, unless they're oversized to compensate). The APS series are also commonly used in developing countries to run household appliances in locations with spotty power availability day-to-day. Tripp Lite's been making this kind of inverter since the 1950's!

If you're using Tripp Lite's APS2448UL plus qty 4 12V 55AH batteries to power a 1200w load, you're going to get way more than 10 minutes! Here's the runtime performance with your 4 12v 55ah batteries at a variety of load levels... Your 10A observation puts you close to 1200w, but it's not uncommon for electronics to pull half, or even way less than the rated power consumption.

If your load is 1200W, you'll get 87 minutes runtime... (and so on down the list).

1200w = 87 min.

1080w = 99 min.

960w = 115 min.

840w = 135 min.

720w = 161 min.

600w = 199 min.

480w = 254 min.

360w = 343 min.

240w = 511 min.

120w = 925 min.

Overkill? Possibly... but UPS runtime, I'm sure most spiceheads would agree, is never something that you can have too much of! Thanks for posting! Rich.